The use of radiation therapy (radiotherapy) to treat cancer is well known. Typically, radiation therapy involves focusing a beam of radiation (e.g., proton, x-ray, or electron radiation) onto a target volume to diagnose an afflicted area or to monitor a tumor or lesion. A beam of high energy proton, x-ray, or electron radiation (“therapeutic radiation”) is subsequently directed into the target volume during treatment.
A radiation therapy device typically includes a surface (e.g., a platform or couch) to support the patient and an overhead radiation source that emits the therapeutic radiation beam. The patient is positioned directly below the radiation source while in a supine position on the couch, and the radiation source directs the beam into the targeted volume (e.g., the tumor being treated). The radiation beam may be moved to “paint” the target volume, or the radiation beam may be shaped so that its cross-section approximates the shape of the target volume, so that the beam falls only on the target volume and not on surrounding, healthy tissue. The strength or intensity of the beam is selected depending on the thickness of the target volume and its depth within the patient, as well as other factors.
During treatment, it is important to keep the patient stationary (immobilized), so that the beam remains pointed at just the target volume, and/or so that the cross-section of the beam at the point where it intersects the target volume does not change. Otherwise, the radiation beam may not cover the entire target volume or might land on tissue outside the target volume.
Fixation or immobilization devices are used to secure a patient's position and keep the patient stationary during radiotherapy. Boluses or shields are used to shape or alter the radiation beam during treatment.
The standard treatment flow is to first scan and image the patient prior to treatment to detect internal organs and locate the target volume (e.g., the tumor). Fixation devices customized for the patient are designed and a treatment plan is generated. Boluses customized to the patient and treatment plan are designed. The designs for fixation devices and boluses (which may be referred to collectively as artifacts) are sent to a manufacturer. The manufactured artifacts are delivered to the treatment center, where they are tested prior to beginning radiotherapy. If changes are needed, the process of interacting with the manufacturer is repeated. The patient then returns and treatment can begin.
The conventional approach described above is problematic for a variety of reasons. First, multiple patient visits are required—at least one visit is required prior to treatment in order to design the artifacts. Also, the need to hire a manufacturer increases costs. Furthermore, time is lost while artifacts are shipped from and perhaps back to the manufacturer.